Some of the secrets to keeping the old forum running died with Cortana, but really I think the size of the posts database was well past the point of what the hardware and/or software could easily handle.

I made a greasemonkey script that moves the user portfolios to the left, makes the forum use the entire browser width, moves the link to MT on the forums navigation, and removes signatures. Cause I hates them forevers.
Only tested in Firefox.

Seems to work in Chrome with Tampermonkey with one minor issue: in post mode, the user info on the left disappears (still takes space, but is blank).
Edit: the second .postbody width is what is causing it, of course (now that I actually look at it).
I found that changing the second style change in the "// Profiles belong on the left!" section to:

I'm using Firefox under Ubuntu. The rollover help text says "contact <z>", but you can't click it because it is displaced away from the "speech bubble", and disappears when you try to get to it. The bubble itself has an associated link, but that leads back to the current thread.